Sauropterygia \Sau*rop`te*ryg"i*a\, n. pl. [NL., fr. Gr. ? a lizard + ?, ?, a wing.] (Paleon.) Same as Plesiosauria.
Source: Webster's Revised Unabridged Dictionary (1913)
Plesiosauria \Ple`si*o*sau"ri*a\, n. pl. [NL. See Plesiosaurus.] (Paleon.) An extinct order of Mesozoic marine reptiles including the genera Plesiosaurus, and allied forms; -- called also Sauropterygia.